The present invention relates to an image read method and apparatus and, more particularly, to an image read method for reading an original image recorded on a recording medium, such as an APS(trademark) (advanced photo system) film, and performing image processes complying with the color of a reference portion of the recording medium, e.g., a film base, and image read apparatus adopting the method.
A film scanner is known as an embodiment of an image processing apparatus for inputting an image recorded on a film to a device, such as a personal computer, which displays the inputted image. A film scanner has been developed for a 135 (35 mm) film. When reading an image, the film scanner first scans an image in a low resolution at high speed, and after the scanned image is displayed by the personal computer (this processing is called xe2x80x9cpreviewingxe2x80x9d and the displayed image is called xe2x80x9cpreview imagexe2x80x9d hereinafter), an area of the image to be read in a high resolution (main scan area) is designated on the preview image. Then, image data, read in the high resolution, of the image in the designated main scan area is transmitted from the film scanner to the personal computer.
FIG. 30 is a block diagram illustrating a configuration of a conventional film scanner 3000.
In FIG. 30, reference numeral 2801 is a light source; and 2802, a film holder for holding a film as a transparent original image. The film holder 2802 is configured movable in the Y direction. Further, reference numeral 2803 denotes a lens system; and 2804 a CCD linear image sensor (referred to as xe2x80x9cCCDxe2x80x9d hereinafter), provided in such a manner that the long side of the CCD 2804 is in the Z direction. In this arrangement, the main scanning direction, namely the long-side direction of the CCD 2804, and the sub-scanning direction, which is the moving direction of the film holder 2802, are orthogonal. Here, following combinations between the light source 2801 and the CCD 2804 are available for reading a color image. Namely,
The respective combinations have different features and defects, and applications of these combination are often determined by trial and error means. Here, the combination (1) is applied as an example.
Reference numeral 2805 denotes an analog image processing unit where setting of gain and clamping is performed on an analog image signal outputted from the CCD 2804; 2806, an analog-digital (A/D) converter for converting an analog image signal into a digital image signal; 2807, an image processing unit, configured with a gate array, capable of applying various image processes to the digital image signal at high speed and outputting a CCD driving pulse; 2808, a line buffer for temporarily storing image data; 2809, an interface (I/F) for communicating with an external device 2810, such as a personal computer; 2811, a system controller, storing program for controlling overall operation in the film scanner 3000, for performing various operation in response to instructions from the external device 2810; 2812, a system bus, configured with an address bus and a data bus, for connecting the system controller 2811, the image processing unit 2807, the line buffer 2808, and the I/F 2809; 2813, a sub-scanning motor, a stepping motor, for moving the film holder 2802 in the sub-scanning direction; 2814, a sub-scanning motor driver for driving the sub-scanning motor 2813 in response to instructions from the system controller 2811; 2815, a sub-scanning position detector for detecting the reference position of the film holder 2802 in the sub-scanning direction by detecting the position of the protuberant shape (not shown) of the film holder 2802 using a photo-interrupter; and 2816, a light-source on/off circuit for turning on and off the light source 2801.
The conventional film scanner 3000 is configured as above, and the film scanner 3000 and the external device 2810, such as a personal computer, communicates by executing software (called xe2x80x9cfirmwarexe2x80x9d hereinafter) stored in the system controller 2811 and software (driver software) for controlling the film scanner 3000 by the external device 2810, and image data read by the film scanner 3000 is transmitted to the external device 2810.
FIG. 31 is a flowchart showing an operational sequence of the film scanner 3000 and the external device 2810. Here, it is assumed that both the film scanner 3000 and the external device 2810 are already turned on, the firmware and the driver software are initiated, and the film is already set at a predetermined position.
First in step S2901, previewing is designated by a user through the external device 2810. Upon designating previewing, the external device 2810 transmits various control information, such as type of film, area to be read, and resolution to be used, to the system controller 2811. In the previewing processing, the area to be read is an entire image recorded on the film, and the resolution is set low.
Next, the system controller 2811 prepares for the previewing by setting the information provided in step S2901 from the external device 2810 in step S2902. Thereafter, the process proceeds to step S2903 where the system controller 2811 receives information from the sub-scanning position detector 2815 and controls the sub-scanning motor 2813 so that the film holder 2802 is moved to a predetermined initial position (referred to as xe2x80x9csub-scanning initial positionxe2x80x9d hereinafter).
Then, in step S2904, the system controller 2811 issues an instruction to turn on the light source 2801 to the light-source on/off circuit 2816, thereby the light source 2801 is turned on. In the succeeding step S2905, the system controller 2811 issues an instruction to output timing signals, such as a CCD driving pulse for reading one line of an image and a RAM address control signal.
Next in step S2906, the image is read line by line by exposing the CCD 2804 for a predetermined period of time while driving the sub-scanning motor 2813 at a predetermined speed. Thereafter, predetermined image processes are performed on the read image data by the image processing unit 2807, and the image data is transmitted to the external device 2810.
After finishing scanning of the designated area of the image in step S2907, the system controller 2811 drives the sub-scanning motor 2813 so as to move the film holder 2802 back to the sub-scanning initial position, and turns off the light source 2801. As soon as all the image data is outputted, the system controller 2811 controls to stop respective functions.
Next, in step S2908, the system controller 2811 is in stand-by state until a next command is received.
In turn, in step S2909, the external device 2810 receives the image data and sequentially displays it on its display screen, thereby providing a preview image to a user.
The process proceeds to step S2910 where the user sets image read (scanning) conditions while watching the preview image on the display screen. Here, similarly to a case where the previewing was designated in step S2901, various information, such as type of the film, area to be read, and resolution to be used, are transmitted to the system controller 2811. Note, in this case, the information for main scanning operation, namely, area to be read designated by the user, and resolution to be used also designated by the user, and so on, are transmitted to the system controller 2811.
In turn, the system controller 2811 receives the image read conditions from the external device 2810 and performs the main scanning under the received image read conditions in step S2911 by repeating the processes in steps S2902 to S2908 as described above.
Thereafter, image data which is transmitted to the external device 2810 is displayed on its display screen as well as stored in a predetermined storage medium (e.g., hard disk, magneto-optical disk, and floppy disk) in step S2912, thereby the entire operation is completed.
However, in the conventional film scanner, especially when reading an image recorded on a negative film, fixed xcex3 correction curves and fixed masking correction coefficients are used to remove undesirable effects of color of the film base on the xcex3 correction and masking correction. It is preferred to measure spectral transmittance of color of each film base, in other words, color of a portion which is not exposed but developed, and determine xcex3 correction curves for each of basic colors, e.g., R, G and B, and masking correction coefficients in accordance with the measured spectral transmittance in order to reduce undesirable effects of the film base color. However, regarding a 35 mm film, it is usually cut in groups of six frames, as shown in FIG. 32, and a very small portion of film base is seen, such as a portion between frames, therefore it is difficult to measure the spectral transmittance of the film base color of the 35 mm film. Accordingly, there is no choice but to use fixed xcex3 correction curves and fixed masking correction coefficients which are stored in advance. However, the color of film base differs, one from the other, and the optimum color reproduction is not always achieved by using the fixed xcex3 correction curves and the fixed masking correction coefficients.
As for an APS(trademark) film, as shown in FIG. 33, the film is rewound into a cartridge without being cut after the film is developed, and a wide portion 3104 which is not exposed but developed exists between the front edge 3102 and the first frame 3103 in the APS(trademark) film.
The present invention has been made in consideration of the above situation, and has as its object to provide an image read method and an image read apparatus capable of achieving good color reproductivity by measuring spectral transmittance of a portion which is not exposed but developed and performing image processes suitable for the measured spectral transmittance.
According to the present invention, the foregoing object is attained by providing an image read method comprising: an image read step of reading an image recorded on a recording medium and outputting image data; a color information determination step of determining color information on basic colors of a reference portion of the recording medium; a parameter setting step of setting a parameter for each color to be used in image signal processes on the basis of the color information determined in the color information determination step; and an image processing step of applying the image signal processes on the image data obtained in the image read step using the parameter set in the parameter setting step.
Further, the object is also attained by providing an image read apparatus comprising: image read means for reading an image recorded on a recording medium and outputting image data; color information determination means for determining color information on basic colors of a reference portion of the recording medium; parameter setting means for setting a parameter for each color to be used in image signal processes on the basis of the color information determined by the color information determination means; and image processing means for applying the image signal processes on the image data obtained by the image read means using the parameter set by the parameter setting means.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.